1. Field of the Invention
The present invention relates to a frame, and more particularly to a frame for a bicycle that has a shock absorbing device to provide a smooth operation.
2. Description of Related Art
With reference to FIG. 6, a conventional bicycle frame with a shock absorbing capability has a front frame (92), a rear frame (90) and a shock absorber (97).
The front frame (92) has a seat tube, a top tube (95) and a bottom bracket shell (93). The seat tube has an upper end and a lower end. The top tube (95) is connected securely to the seat tube near the upper end and has a mounting bracket. The mounting bracket is formed down on the top tube (95) near the seat tube. The bottom bracket shell (93) is connected securely to the lower end of the seat tube and has a connecting bracket (94). The connecting bracket (94) is formed on the bottom bracket shell (93) below the seat tube.
The rear frame (90) is connected pivotally to the front frame (92) and has a lower fork (91) and an upper fork (96). The lower fork (91) is connected pivotally to the bottom bracket shell (93) of the front frame (92) and has a front end and a rear end. The front end of the lower fork (91) is connected to the connecting bracket (94) of the bottom bracket shell (93). Accordingly, the lower fork (91) can move pivotally relative to the bottom bracket shell (93). The upper fork (96) is connected securely to the lower fork (91) and has a lower end, an upper end and a mounting wing. The lower end of the upper fork (96) is connected securely to the rear end of the lower fork (91). The mounting wing is connected to the upper end of the upper fork (96).
The shock absorber (97) is attached pivotally to the front frame (92) and the rear frame (90) between the top tube (95) and the upper fork (96) and has a connecting post and a spring. The connecting post is connected to the mounting bracket of the top tube (95) and the mounting wing of the upper fork (96). The spring is mounted around the connecting post to provide a shock absorbing capability between the front frame (92) and the rear frame (90).
However, the conventional bicycle frame has the following shortcomings.
1. The conventional bicycle frame can provide a shock absorbing capability, but the shock absorbing capability of the conventional bicycle frame is limited, and this cannot provide the conventional bicycle frame to fit with all kinds of the rugged and rough grounds.
2. The shock absorbing capability of the conventional bicycle frame isn't well enough to absorb the shock from the ground, and this will influence the safety and the comfortability of riding the bicycle.
To overcome the shortcomings, the present invention provides a bicycle frame to mitigate or obviate the aforementioned problems.